Electrical firing



Sept. 28, 1965 G. T. BOOP ELECTRIC FIRING 3 Sheets-Sheet 1 Gen 6 7'. 50 0,0

INVENTOR.

Filed Dec.

ATTORNEY Sept. 28, 1965 G. T. BOOP ELECTRIC FIRING I 3 Sheets-Sheet 2 Gene 7'. 500

INVENTOR.

BYm J WM ATTOR/VL'V Sept. 28, 1965 Filed DeC. 26, 1962 G. T. BOOP ELECTRIC FIRING 3 Sheets-Sheet 5 INVENTOR.

ATTO/P/Vi) United States Patent 3,208,378 ELECTRICAL FIRING Gene '1. Boop, Odessa, Tex., assignor to Technical Drilling Service, Inc., Midland, Tex., a corporation of Texas Filed Dec. 26, 1962, Ser. No. 246,971 2 Claims. (Cl. 10220) This invention pertains to electric firing of perforating guns, especially of the shaped charge type.

A principal object of the invention is to provide method and apparatus for this purpose which will be safe and reliable in operation.

Another object of the invention is to provide such a method and apparatus which will indicate at the earths surface during operation which of a plurality of shots is fired, and which will also give afiirmative evidence of the history of its subsurface operation subsequent to firing when the subsurface part of the apparatus is elevated to the surface.

A very important object of the invention is to provide such an apparatus which will be of small diameter so as to pass through 2%" OD. x A3" I.D. tubing.

It is a further object of the invention to provide such an apparatus which will be inexpensive to manufacture, operate, and maintain.

According to the invention a single conductor cable is used to operate the gun from the surface, the subsurface apparatus including electric valve means to distinguish opposite polarity D.C. potentials applied to the cable, one potential operating the motor of a selector switch to connect the cable to a desired gun unit and the opposite polarity firing the charge of the gun unit thus selected. Increase in the motor current indicates positioning of the selector switch at one of the contacts thereof. The motor and switch are irreversible during the operation so that examination of the switch at the surface following use shows how it has performed. The selector switch is above the gun units, being connected therewith by multiple conductors passing inside the housing of the apparatus through interunit seals, which preferably are of the type described in my copending patent application Serial No. 238,303, filed November 16, 1962. Positioning of the switch and gun units at diiferent levels makes it possible to keep the overall diameter of the apparatus sufliciently small to pass the smallest size tubing customarily used.

For a more detailed description of a preferred embodiment of the invention, reference will now be made to the accompanying drawing wherein:

FIGURE 1 is a semi-schematic view, partly in section, showing an overall apparatus according to the invention;

FIGURE 2 is a vertical section, partly in elevation, through the motor and switch portion of the apparatus;

FIGURE 3 is a vertical section through one of the gun units of the apparatus;

FIGURE 4 is a perspective showing the selector switch;

FIGURE 5 is a vertical section through the selector switch;

FIGURE 6 is a section showing the lower bearing of the selector switch; and

FIGURE 7 is a horizontal section through the selector switch.

Referring now to FIGURE 1 there is shown a derrick 10 at the surface of the earth above a bore hole 11. A casing 12 extending part way down the bore from a well head 13 is anchored at its lower end by cement 14. A tubing 15 is supported and sealed at its upper end in the well head by a hanger 16, and is anchored at its lower end in the bore hole by cement 17.

A packing gland is mounted on the well head 13. A single conductor combined electric and supporting 3,208,378 Patented Sept. 28, 1965 'ice cable 21 passes through the stuffing box into the tubing 15. At its upper end the cable passes over crown block 22 and is wound on drum 23 driven by electric motor 24. The end of the cable is connected to slip ring 25.

A source of alternating current electric power (not shown) is connected to conductors 30, 31 leading to transformer primary 32. The transformer secondary 33 is connected through rectifiers 34, 35 to contacts 36, 37 of double throw switch 38. The blade of switch 38 is connected through galvanometer 39 to the brush 40 on slip ring 25. Electric counter 41 is connected to the galvanometer 39. The center tap of the transformer is grounded at 42, which may be a direct connection to the tubing 15.

Connected to the other end of cable 21 is a rope socket 50, collar finder 51, spacer pipe 52, motor switch unit 53, and gun units 54 with double pin connector-seal units 55 therebetween, in addition to several short nipples used in making up the apparatus as an assembly.

Referring now to FIGURE 2, the motor-switch unit 53 is seen to comprise a housing connected at its upper end by sub 61 to spacer pipe 52. Electric conductor rod 62 in the spacer pipe has contacts at its ends for making connection with the collar locator (of conventional design) and the sub 61, the contact 63 at the lower end of rod 62 engaging contact 64 on conductor rod 65 in the sub.

A pin 65A on the lower end of rod 65 engages one of two electric socket connectors 66 and 66a in the upper end of nylon block 67 in the upper part of housing 53. Block 67 has a neck 68 carrying sockets 66 and 66a and fitting into bore 69 in the pin 70 at the lower end of sub 61. An annular rubber cushion disc 71 disposed around neck 68 engages the lower end of pin 70 and the upper end of block 67.

Molded in block 67 are conductors and 80a leading from socket connectors 66 and 66a down to electric valve means (rectifiers) 81 and 81a which are also molded in the block 67. Conductors 82 and 82a lead from the rectifiers 81 and 81a to a connector 83. A skirt 84 on the block provides a recess 85 within which is disposed DC. 110 volt electric motor 86 connected to connector 83 and ground wire 87. Motor 86 incorporates reduction gear whose output 88 is connected to the upper end 89 of the selector switch lead screw.

Another conductor 90 embedded in block 67 branches oil? from conductor 80 and connects to electric valve means (rectifier) 91 also embedded in block 67. A conductor 92 extends down through skirt 84 to make connection with brass strip 93 in the selector switch.

Plural conductors from plural contacts (to be described later) of the selector switch leave the bottom of the switch and enter bore 101 in pin 102 at the upper end of double pin connector 55. The latter is screwed into the lower end of motor switch unit housing 60. An annular rubber cushion disc 103 is disposed between pin 102 and the lower end of the selector switch. The block 67 in which the rectifiers are encapsulated and the selector switch are thus cushioned between rubber discs 71 and 103, with the motor 86 that drives the selector switch disposed inside a recess in the block 67.

Referring now to FIGURE 3 the double pin connector 55 is screwed into the top end of the housing of the uppermost gun unit 54. A conical seat 111 in the pin 103 receives conical plastic seal plug 112 through which pass five of the conductors 100, being molded therein. The plug is held in place by a jam nut 113 screwed into pin 103. An 0 ring seal 114 is disposed 'between plug 112 and seat 111 in annular groove 1 15.

Four of the conductors 100 are connected by pin and socket connectors to plural conductors 121 extending through housing 110 into the pin at the upper end of the J2 next double pin connector 55 therebelow. The other one of the five conductors 100 is connected by one of the pin and socket connectors 120 to conductor 122 to a pin and socket connector 123. The latter connects to electric detonator 124 molded in frangible slug 125.

A length of Primacord 126 has one end molded in slug 125 and extends up therefrom through the back end of shaped charge unit 127. The latter is mounted in housing 110 in conventional fashion, namely, between a socket 128 receiving the back end of the charge unit and a frangible screw 129 in a port 130 in housing 110 adjacent the front end of the charge unit.

The slug 125 is supported in the housing 110 by the Primacord. A second connection to the detonator 124 is made by conductor 132 which connects to spring contactors 133 carried by slug 125 and making contact with the inside of housing 110. The latter is grounded.

The plurality of double pin connectors 55 and the housings 110 of the gun units 54 together form a gun housing within which the several perforating charge units 127 are mounted.

Referring now to FIGURES 4 and 5, the selector switch comprises two cylinders 200, 201 held together by two tie rods 202, 203. A lead screw 204 is rotatably mounted in bearings 205, 206 in the cylinders, the upper end of the screw extending through the upper bearing 205 at 89 for connection to the output shaft 88 of the reduction gear incorporated in motor 86.

Brass strip 93 also extends between cylinders 200, 201. A plastic insulator carrier bar 210 is secured to the bar by screws 211. Recesses in the bar receive electric contacts 212, secured in place by screws 213. The five conductors 100 make connection with the five contacts 212 and may be molded in plastic bar 210.

Ball 240 is mounted in brass nut 241 threaded on lead screw 204. The ball is mounted in a bore 242 and urged outwardly by a spring 243, the latter being held in place by a screw plug 244. The ball is retained in the bore 242 by engagement with bar 210 and contacts 212.

The bore 242 opens into a slot 250 in the nut 241. Face 251 of the slot slides up or down on brass strip 93 as the motor 86 drives the lead screw and moves nut 241. The direction of turning of the lead screw is such as to tend to turn the nut so that face 251 bears against and makes contact with strip 93. Nut 241 thus conducts electricity from the strip 93 to the particular one of the contacts 212 which the nut is opposite. In moving into engagement with a particular contact 212, the ball 240 engages one side of the contact and resists further movement. This loads up the drive motor 86 and the increased current drawn thereby is indicated by galvanometer 39 (see FIG. 1). Then the current drops as the ball passes over the side of the contact and engages the face of the contact. The electric counter 41 registers the number of rises and falls of the current to indicate the position of the selector switch.

In operation, switch 38 is thrown to contact 36 to cause the motor to drive the nut, e.g., upwardly until galvanometer 39 indicates the ball 240 is in engagement with one of the contacts 212 of the selector switch. Then switch 38 is thrown to contact 37 which fires the gun unit connected to the particular contact 212. The time that electric current is supplied to a gun unit to fire same is less than the time the electric current is supplied to the motor to drive ball 240 from one contact 212 to another. This process is repeated to fire each gun unit. When the apparatus is brought to the surface, the position of the selector switch can be checked visually. The selector switch may then be manually reset for the next operation. Thus, with pin 65:: disposed in socket 66a and switch 38 engaging contact 37, motor 36 resets the selector switch.

While a preferred embodiment of the invention has been shown and described, many modifications thereof can be made by one skilled in the art without departing from the spirit of the invention and it is desired to protect 11 by Letters Patent all forms of the invention falling within the scope of the following claims:

I claim:

1. Perforating apparatus comprising an elongated, tubular, metal gun housing including a plurality of tubular sections disposed coaxially in a line, a plurality of metal screw threaded connector units disposed with one connector unit connected between each pair of adjacent sections, each connector unit having a passage therethrough communicating at its ends with the interiors of the adjacent sections,

a plurality of perforating charge units, a plurality of electric detonating means each associated with one of said charge units, each charge unit and its associated detonating means being mounted in one of said tubular sections of the gun housing and extending transversely thereof, each said electric detonating means including a pair of electric terminals one of which is grounded to the gun housing,

a motor-switch unit, an elongated, tubular, motorswitch unit housing within which said motor switch unit is disposed, the motor-switch unit housing being disposed above said gun housing in coaxial alignment therewith, another connector unit connected between the uppermost section of said gun housing and said motor-switch unit housing and having a passage therethrough communicating at its ends with the interiors of said motor-switch unit housing and said uppermost section of said gun housing,

said motor-switch unit including an electric motor having a pair of terminals and a switch having a plurality of stationary contacts and a travelling contact, a lead screw connected to be driven by the electric motor, said lead screw being centrally disposed in said motor-switch unit housing with its axis extending longitudinally of the motor-switch unit housing, said lead screw having a nut thereon carrying said travelling contact, said stationary contacts being disposed along the path of the travelling contact as it is moved by the nut on rotation of the lead screw, said lead screw having a thread of but a single hand whereby continued rotation of the motor in one direction can drive the nut in only one direction.

a plurality of detonator conductors, each conductor connected at one end to the other terminal of said pair of terminals of one of said detonator means and at the other end to a different one of said stationary contacts, said conductors extending from said motorswitch unit housing through said passage through the connector unit connected thereto and to said uppermost section of the gun housing and thence through the gun housing, there being one less conductor passing through each successively lower connector unit, a plurality of pressure seal means each sealing between the passage through one of said connector units and the conductor passing therethrough, each said seal means being separate from each of the other said seal means and each seal means having an axial length less than the distance between the pairs of adjacent charge units, the conductors being exposed between said seal means in the interiors of the several sections of the gun housing, the portions of each conductor within each of said sections including quick attachable and detachable electrical connector means whereby the portion can be readily parted and connected as desired, each of said conductors including quick attachable and detachable electrical connector means in the portion thereof between the stationary contacts of the switch and the connector unit that connects the gun housing and motor-switch unit housing, 3

a single conductor cable entering the top of the motorswitch unit housing, a first electric valve means connected between said cable and said travelling contact of the switch, a second electric valve means connected between said cable and one terminal of said motor, the other terminal of said motor being grounded, said second electric valve means being connected to pass current travelling in the opposite direction through the cable from current passed by the first said electric valve means, whereby upon application of potential between said cable and ground to cause current to flow through said second electric valve means said motor is caused to be driven continuously to move said travelling contact from a position nearer the upper end of said lead screw to a position nearer the bottom of said lead screw in contact with a desired one of said stationary contacts and may pass over other of said stationary contacts en route without pause and without the detonating means connected thereto being discharged, following which said detonating means connected to said desired stationary contact may be detonated with opposite polarity electricity.

2. Combination according to claim 1 wherein the cable includes quick attachable and detachable electric connector means in the portion thereof between the motor and the top of the motor-switch unit housing, and including a portion of a similar quick attachable and detachable electric connector means with which the upper part of the last above said electric connector means may be alternatively connected, and third electric valve means connected between said portion of an electric connector means and said motor, said third electric valve means being connected to pass current through the motor in the opposite direction from that passed by said second electric valve means, whereby on connection of said portion of an electric connector means with said upper part of the electric connector means connected to the cable, said lIIlOtOI' is caused to drive said lead screw in direction to move said travelling contact from a position nearer the bottom of the lead screw to a position nearer the top of the lead screw, thereby resetting the motor-switch unit.

References Cited by the Examiner UNITED STATES PATENTS Oct. 22, 1959, 2 pp. spec, 1 sht. dwg.

SAMUEL FEINBERG, Primary Examiner. 

1. PERFORATING APPARATUS COMPRISING AN ELONGATED, TUBULAR, METAL GUN HOUSING INCLUDING A PLURALITY OF TUBULAR SECTIONS DISPOSED COAXIALLY IN A LINE, A PLURALITY OF METAL SCREW THREADED CONNECTOR UNITS DISPOSED WITH ONE CONNECTOR UNIT CONNECTED BETWEEN EACH PAIR OF ADJACENT SECTIONS, EACH CONNECTOR UNIT HAVING A PASSAGE THERETHROUGH COMMUNICATING AT ITS ENDS WITH THE INTERIORS OF THE ADJACENT SECTIONS, A PLURALITY OF PERFORATING CHARGE UNITS, A PLURALITY OF ELECTRIC DETONATING MEANS EACH ASSOCIATED WITH ONE OF SAID CHARGE UNITS, EACH CHARGE UNIT AND ITS ASSOCIATED DETONATING MEANS BEING MOUNTED IN ONE OF SAID TUBULAR SECTIONS OF THE GUN HOUSING AND EXTENDING TRANSVERSELY THEREOF, EACH SAID ELECTRIC DETONATING MEANS INCLUDING A PAIR OF ELECTRIC TERMINALS ONE OF WHICH IS GROUNDED TO THE GUN HOUSING, A MOTOR-SWITCH UNIT, AN ELONGATED, TUBULAR, MOTORSWITCH UNIT HOUSING WITHIN WHICH SAID MOTOR SWITCH UNIT IS DISPOSED, THE MOTOR-SWITCH UNIT HOUSING BEING DISPOSED ABOVE SAID GUN HOUSING IN COAXIAL ALIGNMENT THEREWITH, ANOTHER CONNECTOR UNIT CONNECTED BETWEEN THE UPPERMOST SECTION OF SAID GUN HOUSING AND SAID MOTOR-SWITCH UNIT HOUSING AND HAVING A PASSAGE THERETHROUGH COMMUNICATING AT ITS ENDS WITH THE INTERIORS OF SAID MOTOR-SWITCH UNIT HOUSING AND SAID UPPERMOST SECTION OF SAID GUN HOUSING, SAID MOTOR-SWITCH UNIT INCLUDING AN ELECTRIC MOTOR HAVING A PAIR OF TERMINALS AND A SWITCH HAVING A PLURALITY OF STATIONARY CONTACTS AND A TRAVELLING CONTACT, A LEAD SCREW CONNECTED TO BE DRIVEN BY THE ELECTRIC MOTOR, SAID LEAD SCREW BEING CENTRALLY DISPOSED IN SAID MOTOR-SWITCH UNIT HOUSING WITH ITS AXIS EXTENDING LONGITUDINALLY OF THE MOTOR-SWITCH UNIT HOUSING, SAID LEAD SCREW HAVING A NUT THEREON CARRYING SAID TRAVELLING CONTACT, SAID STATIONARY CONTACTS BEING DISPOSED ALONG THE PATH OF THE TRAVELLING CONTACT AS IT IS MOVED BY THE NUT ON ROTATION OF THE LEAD SCREW, SAID LEAD SCREW HAVING A THREAD OF BUT A SINGLE HAND WHEREBY CONTINUED ROTATION OF THE MOTOR IN ONE DIRECTION CAN DRIVE THE NUT IN ONLY ONE DIRECTION. A PLURALITY OF DETONATOR CONDUCTORS, EACH CONDUCTOR CONNECTED AT ONE END OF THE OTHER TERMINAL OF SAID PAIR OF TERMINALS OF ONE OF SAID DETONATOR MEANS AND AT THE OTHER END TO A DIFFERENT ONE OF SAID STATIONARY CONTACTS, SAID CONDUCTORS EXTENDING FROM SAID MOTORSWITCH UNIT HOUSING THROUGH SAID PASSAGE THROUGH THE CONNECTOR UNIT CONNECTED THERETO AND TO SAID UPPERMOST SECTION OF THE GUN HOUSING AND THENCE THROUGH THE GUN HOUSING, THERE BEING ONE LESS CONDUCTOR PASSING THROUGH EACH SUCCESSIVELY LOWER CONNECTOR UNIT, A PLURALITY OF PRESSURE SEAL MEANS EACH SEALING BETWEEN THE PASSAGE THROUGH ONE SAID CONNECTOR UNITS AND THE CONDUCTOR PASSING THERETHROUGH, EACH SAID SEAL MEANS BEING SEPARATE FROM EACH OF THE OTHER SAID SEAL MEANS AND EACH SEAL MEANS HAVING AN AXIAL LENGTH LESS THAN THE DISTANCE BETWEEN THE PAIRS OF ADJACENT CHARGE UNITS, THE CONDUCTORS BEING EXPOSED BETWEEN SAID SEAL MEANS IN THE INTERIORS OF THE SEVERAL SECTIONS OF THE GUN HOUSING, THE PORTIONS OF EACH CONDUCTOR WITHIN EACH OF SAID SECTIONS INCLUDING QUICK ATTACHABLE AND DETACHABLE ELECTRICAL CONNECTOR MEANS WHEREBY THE PORTION CAN BE READILY PARTED AND CONNECTED AS DESIRED, EACH OF SAID CONDUCTORS INCLUDING QUICK ATTACHABLE AND DETACHABLE ELECTRICAL CONNECTOR MEANS IN THE PORTION THEREOF BETWEEN THE STATIONARY CONTACTS OF THE SWITCH AND THE CONNECTOR UNIT THAT CONNECTS THE GUN HOUSING AND MOTOR-SWITCH UNIT HOUSING, A SINGLE CONDUCTOR CABLE ENTERING THE TOP OF THE MOTORSWITCH UNIT HOUSING, A FIRST ELECTRIC VALVE MEANS CONNECTED BETWEEN SAID CABLE AND SAID TRAVELLING CONTACT OF THE SWITCH, A SECOND ELECTRIC VALVE MEANS CONNECTED BETWEEN SAID CABLE AND ONE TERMINAL OF SAID MOTOR, THE OTHER TERMINAL OF SAID MOTOR BEING GROUNDED, SAID SECOND ELECTRIC VALVE MEANS BEING CONNECTED TO PASS CURRENT TRAVELLING IN THE OPPOSITE DIRECTION THROUGH THE CABLE FROM CURRENT PASSED BY THE FIRST SAID ELECTRIC VALVE MEANS, WHEREBY UPON APPLICATION OF POTENTIAL BETWEEN SAID CABLE AND GROUND TO CAUSE CURRENT TO FLOW THROUGH SAID SECOND ELECTRIC VALVE MEANS SAID MOTOR IS CAUSED TO BE DRIVEN CONTINUOUSLY TO MOVE SAID TRAVELLING CONTACT FROM A POSITION NEARER THE UPPER END OF SAID LEAD SCREW TO A POSITION NEARER THE BOTTOM END OF SAID LEAD SCREW IN CONTACT WITH A DESIRED ONE OF SAID STATIONARY CONTACTS AND MAY PASS OVER OTHER OF SAID STATIONARY CONTACTS EN ROUTE WITHOUT PAUSE AND WITHOIUT THE DETONATING MEANS CONNECTED THERETO BEING DISCHARGED, FOLLOWING WHICH SAID DETONATING MEANS CONNECTED TO SAID DESIRED STATIONARY CONTACT MAY BE DETONATED WITH OPPOSITE POLARITY ELECTRICITY. 